Tatchbury Mount was built in the early 19th century, possibly for William Timson, or more likely for Henry Thomas Timson, a ‘gentleman of fortune’, who died in 1848. It passed to the Reverend Edward Timson, Master of the New Forest Foxhounds, until his death in 1873, and subsequently to his son, Captain Henry Timson, of the 5th Lancashire Regiment.
Tatchbury was later rented to Mr J.P. Hesletine and then Sir Daniel Fulthorpe Gooch, also of Clewer Park in Berkshire, the third holder of the baronetcy conferred in 1866 on Sir Daniel Gooch, for many years chairman of the Great Western Railway. The third baronet had accompanied Sir Ernest Shackleton in his 1914 Antarctic Expedition as far as South Georgia, signing on as an able seaman on the Endurance.
In 1927, Tatchbury Mount, still owned by the Timson family, was put up for sale and eventually sold to Hampshire County Council as a Colony for Mental Defectives. It opened in 1931 and after a long-use as a secure hospital, the site around it developed and still in use, the original mansion was surprisingly demolished in 2006.